Corrigan et al. developed and tested mRNA lipid nanoparticles (mRNA-LNP) conjugated with fractalkine (CX3CL1) and found that they were able to specifically target CX3CR1+ cells – primarily effector T cells and NK cells – inducing transient expression of the payload mRNA. Administration of fraktalkine-conjugated mRNA-LNPs could be used to induce secretion of IL-2 or cell membrane expression of CD62L in target cells in vivo, with detectable expression of payload expression in up to 95% and 100% of Teff in the peripheral blood of mice and rhesus macaques, respectively. CD62L expression may have enabled lymph node trafficking of CX3CR1+ Teff cells.

Contributed by Lauren Hitchings

ABSTRACT: Selective in vivo reprogramming of cytotoxic effector CD8 T (Teff) cells holds tremendous promise as a therapeutic tool but has not yet been accomplished. Here, we demonstrate that fractalkine-conjugated mRNA lipid nanoparticles (mRNA-LNPs) can specifically target and deliver mRNA to CX3CR1+ Teff cells in vitro and in vivo. In mice, fractalkine-conjugated mRNA-LNPs targeted up to 95% of blood and splenic Teff cells. In addition, delivery of IL-2-encoding mRNA and human CD62L-encoding mRNA to mouse Teff cells enabled robust exogenous IL-2 secretion and CD62L expression. In rhesus macaques, fractalkine-conjugated mRNA-LNPs targeted up to ~100% of peripheral blood Teff cells, and delivery of human CD62L-encoding mRNA enabled cell-surface human CD62L expression on peripheral blood Teff cells and detection of human CD62L+ Teff cells in lymphoid tissue. Collectively, these data demonstrate the potential of natural receptor ligand-based targeting of mRNA-LNPs for rapid, efficient, and transient in vivo modification of Teff cells.

Author Info: 1Department of Microbiology, University of Pennsylvania, Philadelphia, PA, USA. 2Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania , Philadelphia, PA, USA. 3Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. 4Parker Institute for Cancer Immunotherapy, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. 5Division of Microbiology and Immunology, Emory National Primate Research Center, Emory University, Atlanta, GA, USA. 6Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA. 7Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA. 8Division of Animal Resources, Emory National Primate Research Center, Emory University, Atlanta, GA, USA. 9Acuitas Therapeutics, Vancouver, Canada. 10Vaccine and Immunotherapy Center, Wistar Institute, Philadelphia, PA, USA. 11Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA. 12Center for AIDS Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.